Detection rules › Splunk
Potential DCSync (Windows Event Log)
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API) to simulate the replication process from a remote domain controller using a technique called DCSync
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1003.006 OS Credential Dumping: DCSync |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4662 | An operation was performed on an object. |
Rule body yaml
id: '13811.20280'
title: Potential DCSync
description: 'Adversaries may attempt to access credentials and other sensitive information
by abusing a Windows Domain Controller''s application programming interface (API)
to simulate the replication process from a remote domain controller using a technique
called DCSync. -- Threat Actor Association: FIN8 (Syssphinx), Muddled Libra'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4662) OR
"<EventID>4662<") "0x100" ("Replicating Directory Changes all" OR "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2"
OR "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2" OR "9923a32a-3607-11d2-b9be-0000f87a36b2"
OR "89e95b76-444d-4c62-991a-0facbeda640c") |regex user!=".*\$" | table _time, host,
user process, process_*, signature_id, parent_*, parameters | bin span=1s | stats
values(*) as * by _time, host '
techniques:
- credential-access:os credential dumping:dcsync
technique_id:
- T1003.006
data_category:
- Windows event logs
references:
- https://blog.blacklanternsecurity.com/p/detecting-dcsync
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4662) OR "<EventID>4662<") "0x100" ("Replicating Directory Changes all" OR "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2" OR "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2" OR "9923a32a-3607-11d2-b9be-0000f87a36b2" OR "89e95b76-444d-4c62-991a-0facbeda640c")
Stage 2: regex
| regex user!=".*\$"
Stage 3: table
| table _time, host, user process, process_*, signature_id, parent_*, parameters
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
user | regex_match | ".*$" |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>4662<" |
| 1 | "0x100" |
| 1 | "Replicating Directory Changes all" |
| 1 | "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2" |
| 1 | "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2" |
| 1 | "9923a32a-3607-11d2-b9be-0000f87a36b2" |
| 1 | "89e95b76-444d-4c62-991a-0facbeda640c" |